N. A. Kolchanov

Transcription Regulatory Regions Database (TRRD): its status in 2002

Transcription Regulatory Regions Database (TRRD) is an informational resource containing an integrated description of the gene transcription regulation. An entry of the database corresponds to a gene and contains the data on localization and functions of the transcription regulatory regions as well as gene expression patterns. TRRD contains only experimental data that are inputted into the database through annotating scientific publication. TRRD release 6.0 comprises the information on 1167 genes, 5537 transcription factor binding sites, 1714 regulatory regions, 14 locus control regions and 5335 expression patterns obtained through annotating 3898 scientific papers. This information is arranged in seven databases: TRRDGENES (general gene description), TRRDLCR (locus control regions); TRRDUNITS (regulatory regions: promoters, enhancers, silencers, etc.), TRRDSITES (transcription factor binding sites), TRRDFACTORS (transcription factors), TRRDEXP (expression patterns) and TRRDBIB (experimental publications). Sequence Retrieval System (SRS) is used as a basic tool for navigating and searching TRRD and integrating it with external informational and software resources. The visualization tool, TRRD Viewer, provides the information representation in a form of maps of gene regulatory regions. The option allowing nucleotide sequences to be searched for according to their homology using BLAST is also included. TRRD is available at http://www.bionet.nsc.ru/trrd/.

Eukaryotic mRNAs encoding abundant and scarce proteins are statistically dissimilar in many structural features.

It is well known that non‐coding mRNA sequences are dissimilar in many structural features. For individual mRNAs correlations were found for some of these features and their translational efficiency. However, no systematic statistical analysis was undertaken to relate protein abundance and structural characteristics of mRNA encoding the given protein. We have demonstrated that structural and contextual features of eukaryotic mRNAs encoding high‐ and low‐abundant proteins differ in the 5′ untranslated regions (UTR). Statistically, 5′ UTRs of low‐expression mRNAs are longer, their guanine plus cytosine content is higher, they have a less optimal context of the translation initiation codons of the main open reading frames and contain more frequently upstream AUG than 5′ UTRs of high‐expression mRNAs. Apart from the differences in 5′ UTRs, high‐expression mRNAs contain stronger termination signals. Structural features of low‐ and high‐expression mRNAs are likely to contribute to the yield of their protein products.

COMPEL: a database on composite regulatory elements providing combinatorial transcriptional regulation

COMPEL is a database on composite regulatory elements, the basic structures of combinatorial regulation. Composite regulatory elements contain two closely situated binding sites for distinct transcription factors and represent minimal functional units providing combinatorial transcriptional regulation. Both specific factor-DNA and factor-factor interactions contribute to the function of composite elements (CEs). Information about the structure of known CEs and specific gene regulation achieved through such CEs appears to be extremely useful for promoter prediction, for gene function prediction and for applied gene engineering as well. The structure of the relational model of COMPEL is determined by the concept of molecular structure and regulatory role of CEs. Based on the set of a particular CE, a program has been developed for searching potential CEs in gene regulatory regions. WWW search and browse routines were developed for COMPEL release 3.0. The COMPEL database equipped with the search and browse tools is available at http://compel.bionet.nsc.ru/. The program for prediction of potential CEs of NFAT type is available at http://compel.bionet.nsc. ru/FunSite.html and http://transfac.gbf.de/dbsearch/funsitep/ s_comp.html

GeneNet: a gene network database and its automated visualization.

MOTIVATION Gene networks that provide the regulation of physiological processes are the basic feature of organisms. Information regarding the regulation of gene expression and signal transduction pathways is increasing rapidly. However, the information is hard to formalize and systematize. Ways and means for automated visualization of the gene networks based on their formalized description are needed. RESULTS The object-oriented database GeneNet and the software for its automated visualization have been developed. The main principles of a formalized description of the gene network have been worked out. Antiviral response and erythropoiesis are provided as examples to show how this is achieved. The GeneNet graphical user interface written in Java provides automated generation of the gene network diagrams and allows visualization and exploration of the GeneNet database through the Internet. A system of filters allows the selection of particular components of the network for visualization. AVAILABILITY The GeneNet database and its graphical user interface are available at http://wwwmgs.bionet.nsc.ru/systems/MGL/GeneN et/ CONTACT fedor@bionet.nsc.ru

The role of alternative translation start sites in the generation of human protein diversity

According to the scanning model, 40S ribosomal subunits initiate translation at the first (5′ proximal) AUG codon they encounter. However, if the first AUG is in a suboptimal context, it may not be recognized, and translation can then initiate at downstream AUG(s). In this way, a single RNA can produce several variant products. Earlier experiments suggested that some of these additional protein variants might be functionally important. We have analysed human mRNAs that have AUG triplets in 5′ untranslated regions and mRNAs in which the annotated translational start codon is located in a suboptimal context. It was found that 3% of human mRNAs have the potential to encode N-terminally extended variants of the annotated proteins and 12% could code for N-truncated variants. The predicted subcellular localizations of these protein variants were compared: 31% of the N-extended proteins and 30% of the N-truncated proteins were predicted to localize to subcellular compartments that differed from those targeted by the annotated protein forms. These results suggest that additional AUGs may frequently be exploited for the synthesis of proteins that possess novel functional properties.

TATA box polymorphisms in human gene promoters and associated hereditary pathologies

TATA-binding protein (TBP) is the first basal factor that recognizes and binds a TATA box on TATA-containing gene promoters transcribed by RNA polymerase II. Data available in the literature are indicative of admissible variability of the TATA box. The TATA box flanking sequences can influence TBP affinity as well as the level of basal and activated tran-scription. The possibility of mediated involvement in in vivo gene expression regulation of the TBP interactions with variant TATA boxes is supported by data on TATA box polymorphisms and associated human hereditary pathologies. A table containing data on TATA element polymorphisms in human gene promoters (about 40 mutations have been described), associated with particular pathologies, their short functional characteristics, and manifestation mechanisms of TATA-box SNPs is presented. Four classes of polymorphisms are considered: TATA box polymorphisms that weaken and enhance promoter, polymorphisms causing TATA box emergence and disappearance, and human virus TATA box polymorphisms. The described examples are indicative of the polymorphism-associated severe pathologies like thalassemia, the increased risk of hepatocellular carcinoma, sensitivity to H. pylori infection, oral cavity and lung cancers, arterial hypertension, etc.

Identification of sequence-dependent DNA features correlating to activity of DNA sites interacting with proteins.

MOTIVATION The commonly accepted statistical mechanical theory is now multiply confirmed by using the weight matrix methods successfully recognizing DNA sites binding regulatory proteins in prokaryotes. Nevertheless, the recent evaluation of weight matrix methods application for transcription factor binding site recognition in eukaryotes has unexpectedly revealed that the matrix scores correlate better to each other than to the activity of DNA sites interacting with proteins. This observation points out that molecular mechanisms of DNA/protein recognition are more complicated in eukaryotes than in prokaryotes. As the extra events in eukaryotes, the following processes may be considered: (i) competition between the proteins and nucleosome core particle for DNA sites binding these proteins and (ii) interaction between two synergetic/antagonist proteins recognizing a composed element compiled from two DNA sites binding these proteins. That is why identification of the sequence-dependent DNA features correlating with affinity magnitudes of DNA sites interacting with a protein can pinpoint the molecular event limiting this protein/DNA recognition machinery. RESULTS An approach for predicting site activity based on its primary nucleotide sequence has been developed. The approach is realized in the computer system ACTIVITY, containing the databases on site activity and on conformational and physicochemical DNA/RNA parameters. By using the system ACTIVITY, an analysis of some sites was provided and the methods for predicting site activity were constructed. The methods developed are in good agreement with the experimental data. AVAILABILITY The database ACTIVITY is available at http://wwwmgs.bionet.nsc.ru/systems/Activity/ and the mirror site, http://www.cbil.upenn.edu/mgs/systems/acti vity/.

CRASP: a program for analysis of coordinated substitutions in multiple alignments of protein sequences

Recent results suggest that during evolution certain substitutions at protein sites may occur in a coordinated manner due to interactions between amino acid residues. Information on these coordinated substitutions may be useful for analysis of protein structure and function. CRASP is an Internet-available software tool for the detection and analysis of coordinated substitutions in multiple alignments of protein sequences. The approach is based on estimation of the correlation coefficient between the values of a physicochemical parameter at a pair of positions of sequence alignment. The program enables the user to detect and analyze pairwise relationships between amino acid substitutions at protein sequence positions, estimate the contribution of the coordinated substitutions to the evolutionary invariance or variability in integral protein physicochemical characteristics such as the net charge of protein residues and hydrophobic core volume. The CRASP program is available at http://wwwmgs.bionet.nsc.ru/mgs/programs/crasp/.

GeneNet in 2005

The GeneNet system is designed for collection and analysis of the data on gene and metabolic networks, signal transduction pathways and kinetic characteristics of elementary processes. In the past 2 years, the GeneNet structure was considerably improved: (i) the current version of the database is now implemented using ORACLE9i; (ii) the capacities to describe the structure of the protein complexes and the interactions between the units are increased; (iii) two tables with kinetic constants and more detailed descriptions of certain reactions were added; and (iv) a module for kinetic modeling was supplemented. The current SRS release of the GeneNet database contains 37 graphical maps of gene networks, as well as descriptions of 1766 proteins, 1006 genes, 241 small molecules and 3254 relationships between gene network units, and 552 kinetic constants. Information distributed between 16 interlinked tables was obtained by annotating 1980 journal publications. SRS release of the GeneNet database, the graphical viewer and the modeling section are available at http://wwwmgs.bionet.nsc.ru/mgs/gnw/genenet/.

Point mutations within 663-666 bp of intron 6 of the human TDO2 gene, associated with a number of psychiatric disorders, damage the YY-1 transcription factor binding site.

Single base mutations G→A at position 663 and G→T at position 666 of intron 6 of the human tryptophan oxygenase gene (TDO2) are associated with a variety of psychiatric disorders [Comings, D.E. et al. (1996) Pharmacogenetics 6, 307–318]. Binding of rat liver nuclear extract proteins to synthetic double‐strand oligonucleotides corresponding to three allelic states of the region between 651 bp and 680 bp of human TDO2 intron 6 has been studied by gel shift assay. It has been demonstrated that to each allelic state of the region there corresponds a specific set of proteins that interacts with it. With the aid of computer analysis and using specific anti‐YY‐1 antibodies it has been shown that both mutations damage the YY‐1 transcription factor binding site.